This invention relates to gas analyzing systems and more particularly to such systems which may be used to analyze samples of gas drawn from dry and dusty environments, such as lime kilns.
One problem with prior gas analysis systems used to analyze the gases in a hot, dry and dusty environment, such as lime kiln, is that the systems became inaccurate, over time, as their probe lines became clogged with dust. Prior systems, because their lines were clogged, had a slower response time. Inaccuracies also arose because of the adverse effect of "tramp" air, which is air that flows into the kiln through seal leaks, incompletely closed doors and other accidental causes. Such tramp air may have a disproportionate effect on measurements made by the system especially those involving oxygen.
One type of previously disclosed gas monitoring system is shown in the inventor's prior U.S. Pat. No. 4,094,187 ('187 patent) entitled "Stack Gas Analyzing System With Calibrating/Sampling Feature", incorporated by reference herein. In U.S. Pat. No. 4,094,187 patent it is explained that "real-time" gas analyzer uses pipes to convey the gas to a nearby analyzer to permit their immediate analysis and the adjustment of process parameters based upon that analysis. Such rapid adjustments may prevent the exhaust of unacceptable levels of pollutants, and may prevent injury to the kiln and/or associated equipment. In U.S. Pat. No. 4,094,187 patent the calibration gases are supplied to the analyzers through the same gas path used by the samples of the effluent.